Publication Date

September 2008

Abstract

Fuels from renewable biomass already make up part of our energy picture, and that must surely increase. However, relative to petroleum-based fuels, they are thought to generate increased aldehyde and NOx pollutants due to their high content of oxygen and sometimes nitrogen. We are working to explore, explain, and help solve these challenges.

Our two major directions are measuring kinetics with flame molecular-beam mass spectrometry (MBMS) and predicting kinetics using theory, computational quantum chemistry, and our new Reactive Molecular Dynamics methods. We recently built a pioneering MBMS apparatus based on synchrotron VUV-photoionization [Taatjes et al., Science, 308, 1887 (2005)] and have used it to study flames of hydrocarbons, alcohols, aldehydes, ketones, esters, and most recently morpholine. From the data, we have predicted and inferred reaction pathways and the key elementary-reaction kinetics.

Another useful approach is using our Reactive Molecular Dynamics algorithm and RMDff force field, developed for my group's polymer research. This new molecular-simulation method promises to yield powerful, quantitative insights into reactions that convert biomass into fuels, as it has for polymer decomposition. We hope to make the method still more accurate by computing energies with a new, rapid, electronic-structure-based method we have termed BEBOP (bond energies from bond-order populations). When implemented on parallel supercomputers, these methods will open the door to computational experiments for obtaining many types of reaction kinetics.